Biodegradable plastic exposure enhances microbial functional diversity while reducing taxonomic diversity across multi-kingdom soil microbiota in cherry tomato fields

Plastic films are extensively utilized in agroecosystems, and their residues are accumulating in global soil at a worrying rate. Biodegradable films are employed as a substitute for polyethylene (PE) films due to their rapid degradation rate. Although the taxonomic diversity of soil microbiome in response to biodegradable films has been studied, its alterations in functional diversity remain unexplored. Here, we conduct a two-year field experiment in cherry tomato to address how PE and poly (butylene adipate-co-terephthalate) (PBAT) influences soil microbiota across multi-kingdom (bacteria, fungi, and protists) regarding its taxonomic and functional diversity. The results show that PBAT exposure reduces the taxonomic diversity while increasing functional diversity across multi-kingdom domains compared to PE exposure. We further find that the decreased taxonomic diversity under PBAT exposure reduces the complexity of microbial inter-kingdom and internal-kingdom networks. Conversely, PBAT exposure enhances microbial functional diversity (Shannon index) and average genome size, accompanied by elevated abundances of plastic-degrading genes as well as carbon, nitrogen, phosphorus, and sulphur cycling functional genes. Overall, our study indicates that environmental filtration induced by PBAT exposure changes the microbial life adaptive strategies and leads to a decoupling between taxonomic diversity and functional diversity.